循环水养殖系统水体中抗生素抗性基因的污染特征

抗生素的滥用导致了抗生素抗性基因在水产养殖环境中的传播。工厂化循环水养殖系统被认为是环境友好且能够防止抗生素和抗性基因污染沿海水域的养殖模式,但关于抗性基因在循环水养殖系统中的分布和扩散的信息较少。采用高通量定量PCR和基于16S rRNA的Illumina测序分析,研究了来自2个循环水养殖系统各环节水体中的抗性基因和细菌群落结构及动态。2个循环水养殖系统中共检出8种抗性201个亚类的抗性基因,以四环素类、磺胺类和多耐药类抗性基因为主。循环水中四环素类抗性基因tetX和tetG-02相对丰度最高。2个循环水养殖系统水体中的优势菌均为变形菌门和拟杆菌门,但优势细菌属的组成不同。多个菌属与不同亚类的抗性基因之间共现正相关,表明抗性基因在这些菌属中的水平转移与扩散传播。总氮、总磷、氨氮和磷酸盐是影响循环水中抗性基因分布和菌群结构的主要环境因子。以上研究结果表明抗性基因在循环水养殖系统水体中普遍存在,可能对环境构成潜在风险,这将有助于制定有针对性的策略,对水产养殖中的抗性基因进行风险管理和评估。     

Gene expression profiles in the testis associated with testis-ova in adult Japanese medaka (Oryziaslatipes) exposed to 17α-ethinylestradiol

The occurrence of oocytes in the testis (testis-ova) of several fish species is often associated with exposure of estrogenic chemicals. However, induction mechanisms of the testis-ova remain to be elucidated. To develop marker genes for detecting testis-ova in the testis, adult male medaka were exposed to nominal concentration of 100 ng L⁻¹ of 17α-ethinylestradiol (EE2) for 3-5 weeks, and 800 ng estradiol benzoate (EB) for 3 weeks (experiment I), and a measured concentration of 20 ng L⁻¹ EE2 for 1-6 weeks (experiment II). Histological analysis was performed for the testis, and microarray analyses were performed for the testis, liver and brain. Microarray analysis in the estrogen-exposed medaka liver showed vitellogenin and choriogenin as estrogen responsive genes. Testis-ova were induced in the testis after 4 weeks of exposure to 100 ng L⁻¹ EE2, 3 weeks of exposure to 800 ng EB, and 6 weeks of exposure to 20 ng L⁻¹ EE2. Microarray analysis of estrogen-exposed testes revealed up-regulation of genes related to zona pellucida (ZP) and the oocytes marker gene, 42Sp50. Using quantitative RT-PCR we confirmed that Zpc5 gene can be used as a marker for the detection of testis-ova in male medaka.     

零价铁对污泥高温厌氧消化过程中四环素抗性基因及第一类整合子的消减影响

为研究污泥高温厌氧消化过程中零价铁(Fe0)对抗生素抗性基因的消减影响,采用荧光定量PCR方法定量检测了7种四环素抗性基因(TC-ARGs,包括tetA、tetC、tetG、tetM、tetO、tetW和tetX)及第一类整合子int I1基因在厌氧消化过程中的丰度变化,同时检测分析了挥发性脂肪酸(VFAs)的质量浓度变化,并探讨了目标基因与VFAs之间的相关关系.结果表明,适量Fe0(如0.10 g·g~(-1),以Fe0/VSS计)不仅可以强化污泥厌氧消化进程,显著提高总VFAs和乙酸的产生量,而且能够增强TCARGs和int I1基因的消减效果.尽管如此,过量Fe0(如1.17 g·g~(-1),以Fe0/VSS计)对污泥高温厌氧消化过程中TC-ARGs和int I1基因消减的增强效果并不显著,推测可能是由于基因水平转移的发生所导致的.通过相关性分析可知,TC-ARGs(除tetO基因外)和int I1基因与乙酸之间存在显著负相关性,表明乙酸可能对TC-ARGs和int I1基因的消减具有促进作用.     

基于PBPK模型评价三氯乙烯的职业暴露健康风险

三氯乙烯(TCE)作为脱脂和清洗剂被广泛应用于五金、电镀和电子等行业。TCE的职业暴露会产生一系列健康风险,包括过敏症和致癌等。2012年TCE被美国环保局(US EPA)和国际癌症研究机构列为1类致癌物。采用吸附管采样-热脱附/气相色谱-质谱法分析了大连市某企业车间生产工况下空气中TCE浓度。基于生理学的药代动力学(PBPK)模型预测了呼吸暴露途径下TCE在职业工人体内组织中的动态分布、代谢产物生成情况和致癌风险。TCE在不同组织中预测的最大浓度呈现出脂肪 > 肠 > 充分灌注室 > 支气管 > 非充分灌注室 > 肝脏 > 静脉血 > 动脉血的趋势。预测的与致癌有关的代谢产物最大浓度表现为三氯乙酸 > 二氯乙酸 > 三氯乙醛 > S-二氯乙烯基-L-半胱氨酸。在监测的TCE水平(39.2±24.4)μg m^-3下,暴露8 h d^-1,连续暴露20年,基于外暴露评价的职业工人致癌风险均值为1.31×10^-5,该暴露水平下,基于PBPK模型预测的TCE内暴露与外暴露计算的致癌风险水平相近,但基于具有致癌性主要代谢产物的内暴露致癌风险值是外暴露风险值的1.17~1.73倍。TCE的暴露水平越高,基于内暴露方法和外暴露方法的致癌风险评价结果差异越大。敏感性分析表明,心输出血流量和充分灌注室血流量对PBPK模型输出结果具有重要影响。不确定性分析表明,模型参数变化会显著地影响PBPK模型输出结果,但变异在可接受水平。本研究结果说明,评价TCE暴露对人的致癌风险需要考虑其在体内的分布和代谢过程。     

Distribution of environmentally sensitive elements in residential soils near a coal-fired power plant: Potential risks to ecology and children’s health

One hundred and twelve soil samples were collected from residential areas surrounding a coal-fired power plant at Huainan City, Anhui Province, China. The concentrations of environmentally sensitive elements (ESEs As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, V and Zn) in soil samples were determined, and their potential ecological and health risks were assessed. Mean concentrations of ESEs in the downwind soils of the power plant are relatively higher than those in the upwind soils, pointing to a potential ESEs input from coal combustion. The calculated ecological risk of ESEs in soils indicates a relatively low ecological risk. Hazard quotient (HQ) of ESEs in downwind soils is 1.5, suggesting a potential health risk for children. However, the carcinogenic risk values of ESEs in soils are within the acceptable non-hazardous range of 1E−06–1E−04.     

催化剂填料表面微生物对微污染物胁迫的响应

目前复合微污染水源条件下,饮用水中复合微污染物对微生物带来的胁迫效应会引发含氮类消毒副产物生成势(nitrogenous disinfection byproducts formation potential, N-DBPs FP)和抗性基因(antibiotic resistance genes, ARGs)水质风险。本研究基于催化剂(HCLL-S8-M)作为新型生物滤料建立反应器处理砂滤后水,考察生物滤池出水N-DBPs FP和ARGs丰度,对滤料胞外聚合物(extracellular polymeric substance, EPS)进行分析,通过宏基因组学分析水体中微生物群落结构和胁迫效应基因表达水平。结果表明,在相同复合微污染物条件下(磺胺嘧啶和2,4-二氯苯氧乙酸各1 µg·L⁻¹),HCLL-S8-M滤柱出水中卤代乙腈和卤代硝基甲烷的总生成势为522.30 ng·L⁻¹,比椰壳活性炭滤柱出水低171.70 ng·L⁻¹,ARGs相对丰度也比椰壳活性炭滤柱出水低约4倍。这得益于HCLL-S8-M滤柱可以高效去除包括微污染物在内的溶解性有机碳、SUVA和高分子质量的有机物。HCLL-S8-M滤柱和出水中微生物分泌更少的EPS,从而减少的N-DBPs前驱体和削弱ARGs的水平转移。宏基因组学分析结果表明,微生物在HCLL-S8-M滤柱出水中的氧化应激反应功能基因表达比椰壳活性炭滤柱下降。HCLL-S8-M滤柱减弱微污染物对微生物的胁迫效应,降低N-DBPs FP和ARGs,有助于控制微生物应激反应造成间接饮用水水质风险。     

Antibiotic resistant bacteria/genes dissemination in lacustrine sediments highly increased following cultural eutrophication of Lake Geneva (Switzerland)

This study investigates faecal indicator bacteria (FIB), multiple antibiotic resistant (MAR), and antibiotic resistance genes (ARGs), of sediment profiles from different parts of Lake Geneva (Switzerland) over the last decades. MARs consist to expose culturable Escherichia coli (EC) and Enterococcus (ENT) to mixed five antibiotics including Ampicillin, Tetracycline, Amoxicillin, Chloramphenicol and Erythromycin. Culture-independent is performed to assess the distribution of ARGs responsible for, β-lactams (blaTEM; Amoxicillin/Ampicillin), Streptomycin/Spectinomycin (aadA), Tetracycline (tet) Chloramphenicol (cmlA) and Vancomycin (van). Bacterial cultures reveal that in the sediments deposited following eutrophication of Lake Geneva in the 1970s, the percentage of MARs to five antibiotics varied from 0.12% to 4.6% and 0.016% to 11.6% of total culturable EC and ENT, respectively. In these organic-rich bacteria-contaminated sediments, the blaTEM resistant of FIB varied from 22% to 48% and 16% to 37% for EC and ENT respectively, whereas the positive PCR assays responsible for tested ARGs were observed for EC, ENT, and total DNA from all samples. The aadA resistance gene was amplified for all the sediment samples, including those not influenced by WWTP effluent water. Our results demonstrate that bacteria MARs and ARGs highly increased in the sediments contaminated with WWTP effluent following the cultural eutrophication of Lake Geneva. Hence, the human-induced changing limnological conditions highly enhanced the sediment microbial activity, and therein the spreading of antibiotic resistant bacteria and genes in this aquatic environment used to supply drinking water in a highly populated area. Furthermore, the presence of the antibiotic resistance gene aadA in all the studied samples points out a regional dissemination of this emerging contaminant in freshwater sediments since at least the late nineteenth century.     

Algicidal activity of Salvia miltiorrhiza Bung on Microcystis aeruginosa—Towards identification of algicidal substance and determination of inhibition mechanism

The present study was to isolate and identify a potent algicidal compound from extract of Salvia miltiorrhiza and study the potential inhibition mechanism on Microcystis aeruginosa. Column chromatography and bioassay-guided fractionation methods were carried out to yield neo-przewaquinone A, which was identified by spectral analysis. The EC50 of neo-przewaquinone A on M. aeruginosa were 4.68 mg L⁻¹. In addition, neo-przewaquinone A showed relatively higher security on Chlorella pyrenoidosa and Scenedesmus obliquus, with the EC50 values of 14.78 and 10.37 mg L⁻¹, respectively. For the potential inhibition mechanisms, neo-przewaquinone A caused M. aeruginosa cells morphologic damage or lysis, increased malondialdehyde content and decreased the soluble protein content, total antioxidant and superoxide dismutase activity, and significantly inhibited three photosynthesis-related genes (psaB, psbD, and rbcL). The results demonstrated the algicidal effect of neo-przewaquinone A on M. aeruginosa and provided the possible inhibition mechanisms.     

制药废水中抗生素的去除技术研究进展

发酵类抗生素生产废水中残留抗生素及相关物质(残留效价)含量高,对废水生物处理系统微生物群落结构以及废水处理效果影响显著,同时会导致生物处理细菌耐药基因的产生和排放;因此,如何去除废水中残留抗生素及效价是解决抗生素废水处理难题的关键。在前期研究的基础上,提出高浓度抗生素生产废水残留抗生素效价的水处理控制目标,概述了水中抗生素去除的生物和物化技术的最新研究进展,提出了在废水生物处理之前进行抗生素选择性去除的强化催化水解预处理技术方案,结合生物处理之后采用高级氧化技术保障该类废水安全排放,并对未来该类废水处理技术的发展方向提出了建议,以期为行业的可持续发展提供技术支持和科学依据。